Vacuum paper drying machine



June 27, 1933. B. A. ,MALKIN 1,915,432

VACUUM PAPER DRYING MACHINE Filed March 18, 1930 2 Sheets-Sheet l INVENTOR BE R NAR D.A.MALKIN BY G AT T OB NE 8 June 27, 1933. B. A. MALKIN 1,915,432

VACUUM PAPER DRYING MACHINE Filed March 18, 1930 2 Sheets-Sheet 2 INVENTOR BERNARDAMALKI N AITORNEYS Patented June 27, 1933 BERNARD A. MALKIN, OF LACE-ZINE, QUEBEG, GA JXYADA, ASSIGNQR TO. DOMINION ENGINEERING WORKS LIMITED, OF- LAGIEINE, QUEBEC, CANADA vacuum PAPER DRYING nrnci-rrirn Application fil ed March s, 1930. Serrano. 436,806.

This invention relates to vacuum paper drying machines and resides in the provision of improved means for "excluding air from the vacuum dryingchamber.

In all vacuum paperdrying machines now in use the entrance and exit openings of the vacuum drying chamber are sealed by a special arrangement of rolls having sealing strips and rings frictionally engaging there 1 with. The usual roll arrangement comprises a rubber covered roll in rolling contact with two metal rolls. The surface of the rubber roller prevents leakage of air between the contacting surfaces of the several rolls, but

is sufficiently yieldable to permit the paper to pass between the rubber roll and one of the metal rolls. All three rolls are fitted with special sealing rings arranged to prevent leakage of air beyond the ends of the rolls.

The metal rolls are also frictionally engaged by. longitudinally extending sealing strips of rubber or similar material arranged inthe castings in which said rolls operate. These longitudinal sealing strips are heldto the v surface of the metal rolls by a pressure of approximately 5 to 15 pounds per square inch and are lubricated by water supplied thereto from suitable ponds maintained in said castings. r

WVhen a paper drying machine constructed as described in the foregoing is operated at high speeds, it isfound that the rubber sealing strips engaging the metal rolls consume considerable power, and deteriorate due to 3 the friction to which they are subjected, ne-

cessitating frequent stoppage of the machine for the purpose of replacing these sealing strips. Another disadvantage resides in the fact that the pressure with which the sealing 0 strips are held to the surfaces of the metal rolls results in wear and tear on the sealing rolls. f a With the foregoing in mind the purpose of the present invention is to eliminate the 5 sealing strips and rings above referred to and to provide improved means for'excluding air from the drying chamber.

According to this invention, suitable castings are arranged close to the surfaces of 5 the rolls between which thepaper passes into or out of'the drying chamber. These castings are cored out to provide a series of continuous sealing chambers which extend, in parallel relation, both longitudinally and circumferentially withrespect to the exposed surfaces of the rolls. This arrangement of chambers provides passageways of labyrint-hian form, through which all air leaking past the'rollers' must flow on the way to the interior of the drying chamber. Certain of these sealing chambers are connected to vacuum pumps or other suitable source of vacuum so that practically all of the air flowing between the rollers and the castings in which the sealing chambers are formed is picked up by the vacuum pumps before reaching the interior of the drying chamber. Proceeding now to a more detailed discussion of the invention, reference will be had to the accompanying drawings in which,

Figure l is a fragmentary vertical sec-' tional view through one end of a drying chamber equipped with my invention.

Figure 2 is a fragmentary transverse sectional view taken substantially along the 75 line 22 of Figure 1.

Figure 3 is a fragmentary perspective View of the construction shown in Figures 1 and 2.

Referring more particularly to the drawings, 11 designates a vacuum drying chant ber equipped with the usual arrangement of dryer felts and felt carrying rolls generally indicated at 12. The end of the drying chamber shown in the present instance may be taken to represent either the exit or entrance end, as my invention is equally ap plicable to both.

Instead of the usual roll arrangement comprising a rubber covered roll interposed between two metal rolls, I have shown only two rolls including a metal'roll 13 and a rubber covered roll 14, as, with the use ofmy invention, the remaining metal roll customarily employed may be dispensed with. The paper web indicated at 15 passes in or out (as the 9 case may be) between the metal roll 13-and the rubber covered roll 14. I

My invention consists, essentially, in providing a casting structure generally indicated at 16 and havingits inner surface curved 20, 21, 22 and'23. Thesesealin at 16 to provide for the passage ofthe paper web 15 between the rolls 13 and 14. The hori-= zontally extending )ortions of thesealing chambers located a ve the openings 16 form, in effect, alabyrinthian passage ex,-

tending circumferentially' a'round the exposed surface of the roll 14. The lowerhorizontal portions of the sealing chambers positionedbelow the opening 16 form in like manner, a labyrinthian-passage extending circumferentially around the lower, exposed portion of the roll 13.v The vertical or circumferentially extending portions of the sealing chambers which are located at the ends. of the openings 16. form, in effect, labyrinthian passages extending from the ends of the openings 16 towards the ends of thelroll s' 13 and 14 and in the longitudinal" direction of said rolls. The labyrinthian passages thus provided along the length of the rolls 13 and 14 and at opposite ends of said rolls serve'to retard the inflow'of air towards the interior of the drying chamber 11, thisbeing a well known elfectof a labyrinthian passagewith respectto the flow of air and similar substances 7 c.

"The chambers 17, 18, 19,20 and 22'serve as expansion chambers into which the air is permitted to expand during its passage be- I tween the casting structure 16 and the adjacent surfaces of the rolls 13 and 14. The

chambers 21 and 23 are, however, made considerably larger than the remaining chamhere are each connected in a suitablemanv fner to a vacuum pump A or other suitable source of vacuum. As the air under atmospheric pressure flows between the casting structure 16 and the opposing surfaces of the rolls 13 and 14, the pressure of the inflowing air is materially reduced, due to the .la'byr-inthian passages afforded by the presence t and rig-id beam 35 may be arranged to extend, I

of the horizontally and circumferentially extending sealing chambers 17, 18,19, 20,21, 22 and 23. .A considerable portion of'the air which passes inwardly beyond the innermost expansion chamber 20 isexhausted through the chamber 21 and the vacuum pump A connected therewith. The air which succeeds in 1 passing inwardly beyond the first exhaust chamber 21 isinitially retardedby the ex- 7 pa'nsi'on chamber 22 and is then exhausted through the second exhaust chamber '23 and the vacuum pump connected therewith.

Chambers 21 and 23 may be connected to the same source of vacuum, but it is preferred that these chambers be connected to separate pumps as, in actual practice, it may be desirable that the chamber 21 be connected to a vacuum ump of greater volume than that connecte to the chamber 23, as most of the air leaking in between the rolls 13 and 14 and the casting structure 16 is exhausted via chamber 21 and the vacuum pump connected therewith. I i

The casting structure 16, in which the sealing chambers 17 to 23 inclusive are formed, may be of any desired sectional structure to facilitate assembly and disassembly. In the present instance, the casting structure is shown as comprising an'upper section 16, a lower section 16?) and end sections 160. The

end sections 160, as, shown to advantage in Figure 2, may be suitably embodied in the wall structure of the dr ing chamber 11 to formthe side frames t ereof. These end sections 160 are joined to the upper section 1 16a, and to the lower section 1612 by the'flanges 16d and bolts 16c. The sections 16a and 16?) are secured together by the flanges 16f and bolt 16g. U

The upper castingsection 16a is formed to presenta horizontal flange 25 and a vertical age 26. The horizontal flange 25 rests on the top wall 27 of the drying chamber 11.

This wall 27 is provided with a vertical flange 28. opposing the flange 26. A plurality of adusting members 29. are arranged between the 00 members 29 are in the form ofturnbuckles" opposing flanges 26 and 28. These adjusting by means of which adjustment maybemade atdiflerent points along 'the length of the casting section lflato compensate for warp er casting section 16b is formed with a de- M pending vertical flange-30 and a horizontal ange 31. The flange 30' overlaps a vertical flange 32 carried by the front wall 33 of the drying chamber. Flange 32 carries a series of adjustable pressure applying bolts 34 engaging the horizontal flange 31 and adapted to functionin the manner described in connection with "pressure applying devices 29.

As'shown in Figure 1, a relatively strong vides a relatively strong and rigid abutment for 'a "series of adjusting devices 36 which bear against the'fron't portion of casting sec- 1 tion'loa and serve the same purpose as the ad- Y j'usting devices 29 and '34 previously referred to. p From the foregoing, it willbe apparent thatthe present invention provides means for excluding or substantially excluding air from the drying chamber without bringing the air excluding means into actual frictional contact with the surfaces of the rolls between tween the rolls and the sealing strips and rings heretofore employed for excluding air from the drying chamber.

A vacuum paper drying machine equipped with air excluding means designed in accord- I ance with this invention may be successfully operated at higher speeds than have heretofore been practically possible with drying machines of this type. Y

Having thus described my invention, what I claim is e 1. ,In a vacuum paper drying machine, the combination with the vacuum drying chamber and the sealing rolls between which the paper passes into or out of the drying chamber, of a structure extending longitudinally and circumferentially with respect to the exposed surfaces of said rolls, said structure being formed with a plurality of sealing chambers affording passages of labyrinthian form through which air, leaking past the rolls, is

forced to pass on its way to the interior of the drying chamber, and means for placing one or more of said sealing chambers under vacuum. j

2. The combination with a vacuum chamber having entrance and exit openings and rolls arranged in said openings of means for preventing the entrance of air between the rolls and the adj acent wall portions of said openings, said means comprising a. structure projecting inwardly from the edge portions of said openings and extending longitudinally and circumferentially with reference to the exposed surface of said rolls, said struc:

time being formed with a plurality of spaced sealing chambers extending longitudinally of the rollers and a plurality of spaced sealing chambers extending circumferentially of the rolls, said last mentioned chambers communicating with said first mentioned chambers and means for placing one or more of said chambers under vacuum.

3. The combination with avacuum chamber equipped with rolls between which ma terial is passed into and out of said'chamber,

of means, including a source of vacuum other than that afforded by the vacuum chamber, for eifecting a vacuum withdrawal of air tending to leak inwardly between the rolls and adjacent wall portions of said chamber.

4. The combination with a vacuum chamber equipped with rolls between which material is passed into and out of said chamber, of means arranged to form labyrinthian passages retarding leakage of air between the rolls and adjacent wall portions of the chamber and means including a source of vacuum other than that afforded by the vacuum chamber, for causing .air entering said passages to be extracted therefrom prior to reaching the interior of the vacuum chamber.

5. The combination of a vacuum chamber equipped with rolls between which sheet material is passed during its travel into or out of said chamber, a sealing member arranged adjacent to each roll and having its roll opposing surface grooved to retard the leakage of air across said surface and into the vacuum chamber and a source of vacuum other equipped with a pair of engaging rolls between which sheet material is passed during its travel into and out of said chamber and means for preventing leakage of air between the roll surfaces and adjacent wall surfaces of said chamber comprising a sealing member joined to one of said wall portions and extending longitudinally with respect to the surface of the adjacent roll, said sealing member presenting a roll opposing surface positioned close to the roll and provided with a series of grooves forming air expansion chambers tending to retard leakage of air across the opposingroll surface and into, the vacuum chamber, and a source of suction other than that afforded by the vacuum chamber connected to one or more of said air expansion chambers so that outside air entering the passages afforded between the rolls and their associated sealing members is extracted from said passages prior to reaching the interior of the vacuum chamber.

In witness whereof I have hereunto set my 

